Solid-state image pickup device, method for manufacturing the same, and image pickup apparatus

ABSTRACT

A solid-state image pickup device is provided which includes a plurality of pixels provided in a semiconductor substrate, the pixels including a plurality of photoelectric conversion portions and MOS transistors which selectively read out signals therefrom, at least one organic photoelectric conversion film on the photoelectric conversion portions, and an isolation region provided in the organic photoelectric conversion film at a position corresponding to between the pixels to perform optical and electrical isolation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solid-state image pickup device, amethod for manufacturing the same, and an image pickup apparatus.

2. Description of the Related Art

A semiconductor image sensor has a plurality of pixels functioning asphotoelectric conversion portions. As this semiconductor image sensor,for example, there may be mentioned a CMOS sensor in which MOStransistors are used as elements which selectively read out a pluralityof pixels and a charge coupled device (CCD) in which charges aretransferred in a silicon substrate and are then read out, and these twoimage sensors are each a semiconductor device which reads out signals ofpixels. In recent years, because of features of the CMOS sensor, such aslow voltage, low power consumption, and multifunctionality, muchattention has been paid thereto as an image pickup element, such as amobile phone camera, a digital still camera, and a digital video camera,and hence the range of the use of the CMOS sensor has been increased.

In addition, as a color image sensor, a technique has been generallyused in which a color filter having, for example, three types of colorsRGB (RGB Bayer arrangement is commonly used) is formed in each pixel,and spatial color separation is performed. According to this technique,when spectral characteristics of a color filter are appropriatelyadjusted, superior color reproduction can be achieved. However, sincelight absorption by the color filter itself is not small, there has beena fundamental problem in that light incident on the image sensor may notbe sufficiently effectively utilized.

In addition, since spatial color separation is performed, pixels of theimage sensor may not be effectively used. For example, when the numberof green pixels is small, the resolution of luminance signals isdegraded, and when the number of red and/or blue pixels is small, theresolution of color signals is degraded, that is, false color signalsare disadvantageously generated.

Furthermore, concomitant with a reduction in size of the image sensorand an increase in number of pixels thereof, recently, the cell size ofone pixel has been reduced to 2.0 μm square or less. Accordingly, thearea and the volume per one pixel are naturally reduced, and as aresult, the amount of saturation signals and the sensitivity aredecreased, so that the image quality is degraded. Hence, when R/G/Gsignals can be obtained by one pixel or two to three pixels withoutreducing the cell size, while the sensitivity and the amount ofsaturation signals are each maintained at a predetermined level, thespatial luminance and the chroma resolution can be maintained.

As a method for solving the above problem, in recent years, an imagesensor using a multilayer organic photoelectric conversion film has beendeveloped (for example, see Japanese Unexamined Patent ApplicationPublication No. 2003-234460). As shown in FIG. 9, an organicphotoelectric conversion film 126 having a sensitivity to blue (B), anorganic photoelectric conversion film 128 having a sensitivity to green(G), and an organic photoelectric conversion film 130 having asensitivity to red (R) are sequentially laminated to each other.According to the image sensor described above, by the above structure,B/G/R signals can be separately obtained from one pixel, and thesensitivity can be improved.

On the other hand, a device has been realized in which only one organicphotoelectric conversion film is formed to extract one color signaltherefrom, and two color signals are extracted by silicon (Si) bulkspectroscopy (for example, see Japanese Unexamined Patent ApplicationPublication No. 2005-303266). In addition, the inventors of the presentinvention have proposed, by using the structure of awhole-area-open-type CMOS image sensor (or also referred to as“back-illuminated CMOS image sensor”), a structure capable of improvingthe sensitivity and color reproduction (for example, see JapaneseUnexamined Patent Application Publication No. 2008-258474).

The structure of one of these related techniques is shown in FIGS. 10Ato 11B by way of example.

As shown in FIGS. 10A and 10B, for example, although lower electrodes141 are independently formed for respective pixels 121, an organicphotoelectric conversion layer 144, a blocking film 146 for decreasing adark current, and the like are not separated for the respective pixels121.

Hence, optical factors and electrical factors between the pixels 121degrade spatial resolution capability and are partially responsible forcolor mixture. As the optical factors, for example, a phenomenon inwhich light incident on one pixel directly leaks in an adjacent pixelthereto may be mentioned, and as the electrical factors, for example, aphenomenon in which carriers generated by photoelectric conversion oflight incident on one pixel leak in an adjacent pixel thereto may bementioned.

When the organic photoelectric conversion film 144 has a smallthickness, since a voltage is applied between transparent electrodes,influences of the above-described optical factors and electrical factorsare relatively small. However, in order to improve the spectralcharacteristics, hereinafter, the thickness of the organic photoelectricconversion film 144 tends to be increased. In this case, it becomes moredifficult to ignore problems, such as occurrence of color mixture anddegradation in spatial resolution capability, and hence improvementsthereof have been strongly desired.

As one example of a method to suppress the color mixture and thedegradation in spatial resolution capability, as shown in FIG. 11A, thestructure has been disclosed in which a first electrode 162, a bufferlayer 163, a photoelectric conversion layer 164, and a second electrode165 are provided on a substrate 161 and are isolated for each element(for example, see Japanese Unexamined Patent Application Publication No.2008-53252). In addition, as shown in FIG. 11B, the structure has beendisclosed in which a first electrode 162, a buffer layer 163, and aphotoelectric conversion layer 164 are provided on a substrate 161 andare isolated for each pixel and in which an electrical insulatingportion 169 is formed at an isolation portion (for example, see JapaneseUnexamined Patent Application Publication No. 2008-53252). As a methodfor isolating the photoelectrical conversion layer 164 and the bufferlayer 163 for each element, etching or lift-off has been used. However,in the etching, degradation in characteristics caused by damage andcontrol of selection ratio are problems, and in the lift-off, forexample, pattern accuracy, fine pattern handling, and dust generationare problems. Furthermore, although electrical isolation has beenproposed, optical isolation to directly avoid the color mixture has notbeen disclosed, and the effect of preventing the color mixture has notbeen sufficient.

SUMMARY OF THE INVENTION

The problem to be solved is that although the electrical isolation isperformed, the optical isolation to avoid the color mixture is notsufficient.

A solid-state image pickup device using an organic photoelectricconversion film according to an embodiment of the present invention isable to suppress the occurrence of color mixture and the degradation inspatial resolution capability, which are caused by electrical andoptical factors.

A solid-state image pickup device according to an embodiment of thepresent invention includes a plurality of pixels provided in asemiconductor substrate, the pixels including a plurality ofphotoelectric conversion portions and MOS transistors which selectivelyread out signals therefrom, at least one organic photoelectricconversion film on the photoelectric conversion portions, and anisolation region provided in the organic photoelectric conversion filmat a position corresponding to between the pixels to perform optical andelectrical isolation.

In the solid-state image pickup device according to an embodiment of thepresent invention, since the isolation region which performs optical andelectrical isolation is formed in the organic photoelectric conversionfilm at the position corresponding to between the pixels, light incidenton one pixel is prevented from directly leaking in an adjacent pixelthereto. In addition, carriers generated by photoelectrical conversionof light incident on one pixel are prevented from leaking in an adjacentpixel thereto.

A method for manufacturing a solid-state image pickup device accordingto an embodiment of the present invention includes the steps of forminga plurality of pixels in a semiconductor substrate, the pixels includinga plurality of photoelectric conversion portions and MOS transistorsselectively reading out signals therefrom, forming at least one organicphotoelectric conversion film on the photoelectric conversion portions,and forming an isolation region performing optical and electricalisolation in the organic photoelectric conversion film at a positioncorresponding to between the pixels.

According to the method for manufacturing a solid-state image pickupdevice according to an embodiment of the present invention, since theisolation region which performs optical and electrical isolation isformed in the organic photoelectric conversion film at the positioncorresponding to between the pixels, light incident on one pixel isprevented from directly leaking in an adjacent pixel thereto. Inaddition, carriers generated by photoelectrical conversion of lightincident on one pixel are prevented from leaking in an adjacent pixelthereto.

An image pickup apparatus according to an embodiment of the presentinvention includes a light condensing optical portion condensingincident light, an image pickup portion having a solid-state imagepickup device which receives light condensed by the light condensingoptical portion and performs photoelectrical conversion of the light,and a signal processing portion processing a signal which isphotoelectrical-converted by the solid-state image pickup device and isoutput from the image pickup portion, and the solid-state image pickupdevice includes a plurality of pixels provided in a semiconductorsubstrate, the pixels including a plurality of photoelectric conversionportions and MOS transistors selectively reading out signals therefrom,at least one organic photoelectric conversion film on the photoelectricconversion portions, and an isolation region provided in the organicphotoelectric conversion film at a position corresponding to between thepixels to perform optical and electrical isolation.

In the image pickup apparatus according to an embodiment of the presentinvention, since the solid-state image pickup device according to anembodiment of the present invention is used, a solid-state image pickupdevice in which the spatial resolution capability is enhanced and thecolor mixture is suppressed is used.

In the solid-state image pickup device according to an embodiment of thepresent invention, since light incident on one pixel is prevented fromdirectly leaking in an adjacent pixel thereto, and carriers generated byphotoelectrical conversion of light incident on one pixel is preventedfrom leaking in an adjacent pixel thereto, the spatial resolutioncapability can be enhanced, and the color mixture can be suppressed. Asa result, a high-quality image can be obtained with high accuracy.

In the method for manufacturing a solid-state image pickup deviceaccording to an embodiment of the present invention, since lightincident on one pixel is prevented from directly leaking in an adjacentpixel thereto, and carriers generated by photoelectrical conversion oflight incident on one pixel is prevented from leaking in an adjacentpixel thereto, the spatial resolution capability can be enhanced, andthe color mixture can be suppressed. As a result, a solid-state imagepickup device capable of forming a high-quality image with high accuracycan be manufactured.

In the image pickup apparatus according to an embodiment of the presentinvention, since the spatial resolution capability can be enhanced, andthe color mixture can be suppressed, a high-quality image can beadvantageously recorded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic structural perspective cross-sectional viewshowing a first example of a solid-state image pickup device accordingto a first embodiment of the present invention;

FIG. 1B is a partial cross-sectional view of the solid-state imagepickup device shown in FIG. 1A;

FIG. 2A is a schematic structural perspective cross-sectional viewshowing a second example of the solid-state image pickup;

FIG. 2B is a partial cross-sectional view of the solid-state imagepickup device shown in FIG. 2A;

FIGS. 3A and 3B are each a schematic structural cross-sectional viewshowing a modified example of the solid-state image pickup device;

FIGS. 4A and 4B are each a schematic structural cross-sectional viewshowing a modified example of the solid-state image pickup;

FIGS. 5A to 5C are manufacturing process cross-sectional views showing afirst example of a method for manufacturing a solid-state image pickupdevice according to a second embodiment of the present invention;

FIGS. 6A and 6B are manufacturing process cross-sectional views showingthe first example of the method for manufacturing a solid-state imagepickup device;

FIGS. 7A to 7D are manufacturing process cross-sectional views showing asecond example of the method for manufacturing a solid-state imagepickup device;

FIG. 8 is a block diagram showing one example of an image pickupapparatus according to a third embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view showing one example of arelated technique;

FIG. 10A is a schematic structural perspective cross-sectional viewshowing one example of a solid-state image pickup device of a relatedtechnique;

FIG. 10B is a schematic cross-sectional view of the solid-state imagepickup device shown in FIG. 10A; and

FIGS. 11A and 11B are each a schematic cross-sectional view showing oneexample of a related technique.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, modes (hereinafter referred to as “embodiments”) forcarrying out the present invention will be described.

1. First Embodiment

[First Example of Structure of Solid-State Image Pickup Device]

A first example of the structure of a solid-state image pickup device 1according to a first embodiment of the present invention will bedescribed using a schematic structural perspective cross-sectional viewand a partial cross-sectional view shown in FIGS. 1A and 1B,respectively. In FIGS. 1A and 1B, as one example using the solid-stateimage pickup device 1 according to the first embodiment of the presentinvention, a whole-area-open-type CMOS image sensor is shown.

As shown in FIG. 1A, a plurality of pixels 21 which includesphotoelectric conversion portions (such as photodiodes) 22 convertingincident light to electrical signals, transistor groups 23 (some of themare shown in the figure) composed of MOS transistors, and the like isformed in an active layer 12 formed of a semiconductor substrate 11. Thetransistor groups 23 each include, for example, a transfer transistor,an amplifier transistor, and a reset transistor. For the semiconductorsubstrate 11, for example, a silicon substrate is used. Furthermore, asignal processing portion (not shown) processing a signal charge readout from each of the photoelectric conversion portions 22 is alsoformed.

Along a part of the periphery of each pixel 21, for example, in a row ora line direction between adjacent pixels 21, an element isolation region24 is formed.

In addition, a wire layer 31 is formed at a front surface side (a lowerside of the semiconductor substrate 11 in the figure) of thesemiconductor substrate 11 in which the photoelectric conversionportions 22 are formed. This wire layer 31 includes wires 32 and aninsulating film 33 covering the wires 32. A support substrate 35 isformed on the wire layer 31. This support substrate 35 is formed, forexample, of a silicon substrate.

Furthermore, in the solid-state image pickup device 1, an insulatingfilm (not shown) having an optical transparency is formed at a rearsurface side of the semiconductor substrate 11. In addition, on thisinsulating film (an upper surface side in the figure), first electrodes41 are formed.

For the first electrode 41, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

In addition, an electrode isolation region 42 is formed between thefirst electrodes 41 so as to correspond to between the pixels 21. Thatis, the first electrodes 41 are independently formed to correspond tothe respective pixels. In addition, the surface of each of the firstelectrodes 41 and the surface of the electrode isolation region 42 arepreferably planarized to be flush with each other.

Furthermore, an organic photoelectric conversion film 44 is formed onthe first electrodes 41 and the electrode isolation region 42.

In addition, depending on the difference in ionization potential betweenthe first electrode 41 and the organic photoelectric conversion film 44,a blocking film (not shown) similar to a blocking film 46 which will bedescribed later may be necessary between the first electrodes 41 and theorganic photoelectric conversion film 44 in some cases.

The organic photoelectric conversion film 44 is formed, for example, tohave a thickness of 100 nm. This thickness may be optionally selected.As this organic photoelectric conversion film 44, for example, polymersof phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole,pycoline, thiophene, acetylene and diacetylene or derivatives thereofmay be used.

Furthermore, for example, there can be preferably used metal complexdyes, cyanine-based dyes, merocyanine-based dyes, phenylxanthene-baseddyes, triphenylmethane-based dyes, rhodacyanine-based dyes,xanthene-based dyes, macrocyclic aza-annulene-based dyes, azulene-baseddyes, naphtoquinone-based dyes, anthraquinone-based dyes, chaincompounds obtained by condensation between condensed polycyclic aromaticcompounds, such as anthracene and pyrene, and aromatic or hetero ringcompounds, two nitrogen-containing heterocyclic rings, such asquinoline, benzothiazole, and benzooxazole, bonded through a squaryliumgroup and/or a croconic methine group, and cyanine analogue dyes bondedby a squarylium group and/or a croconic methine group.

In addition, as the metal complex dyes, dithiol metal complex dyes,metal phthalocyanine dyes, metal porphyrin dyes or ruthenium complexdyes are preferable, and the ruthenium complex dyes are particularlypreferable; however, the metal complex dyes are not limited to thosementioned above.

Furthermore, an isolation region 45 is formed in the organicphotoelectric conversion film 44 at a position corresponding to betweenthe pixels 21. Hence, the isolation region 45 is formed along upper sideperipheries of the pixels 21. That is, the organic photoelectricconversion film 44 is divided by the isolation region 45 so as tocorrespond to the pixels. This isolation region 45 is formed of animpurity region which has insulating properties and which reflects orabsorbs incident light. For example, the isolation region 45 is formedby implanting an impurity, such as nitrogen (N) or oxygen (O), in theorganic photoelectric conversion film 44, for example, at a dose of1×10¹¹ cm⁻² or more.

As an impurity which forms an isolation region 45 optically absorbinglight, for example, carbon (C), oxygen (O), and nitrogen (N) may bementioned, and when at least one of these impurities is implanted, anabsorption layer in which bond absorption of an organic compound occurscan be formed.

As an impurity which forms an isolation region 45 optically reflectinglight, for example, hydrogen (H), helium (He), oxygen (O), and nitrogen(N) may be mentioned, and when at least one of these impurities isimplanted, an isolation region 45 having a low refractive index comparedto that of the organic photoelectric conversion film 44 is formed.Hence, optical reflection occurs at an interface between the organicphotoelectric conversion film 44 and the isolation region 45. Inaddition, in order to form the interface at which optical reflectionoccurs, the impurity concentration distribution is preferably made assteep as possible. In addition, as the impurity which forms an isolationregion 45 optically reflecting light, a metal ion element, such astitanium (Ti), zirconium (Zr), hafnium (Hf), or tungsten (W), having ahigh reflectance may also be mentioned.

Next, among impurities which impart electrical insulating properties,there is an impurity which is turned into an electrically insulatingmaterial when being implanted in the organic photoelectric conversionfilm 44, and for example, oxygen (O) and nitrogen (N) may be mentioned.

Among the impurities mentioned above, an impurity which forms a regionperforming optical isolation (absorption or reflection) in the organicphotoelectric conversion film 44 and an impurity which forms a regionhaving electrical insulating properties therein can be selected, and asan impurity which can achieve the above-described optical and electricalisolation, for example, oxygen (O) and nitrogen (N) may be mentioned.

In addition, when an impurity which forms an isolation region impartingoptical absorption or reflection properties and an impurity which formsan isolation region imparting electrical insulating properties are bothimplanted in the organic photoelectric conversion film 44, an isolationregion 45 performing optical and electrical isolation may also beformed.

Alternatively, in a region of the organic photoelectric conversion film44 in which bonds of an organic photoelectric conversion material arebroken, the isolation region 45 is formed. For example, when helium(He), argon (Ar), nitrogen (N), oxygen (O), or the like is ion-implantedin the organic photoelectric conversion film 44 at a high dose, damageis done to bonds between molecules and/or atoms (for example, the bondsare broken thereby), and as a result, the isolation region 45 is formed.

In addition, in the isolation region 45 formed by ion-implantation of animpurity in the organic photoelectric conversion film 44, some impuritythus implanted shows the above optical and/or insulating properties, andsome impurity forms a compound in the organic photoelectric conversionfilm 44 and shows the above properties.

In addition, although the isolation region 45 is formed to coincide withthe electrode isolation region 42, as for the relative relationshipbetween the width of the isolation region 45 and the width of theelectrode isolation region 42, the widths thereof may not be necessarilyequal to each other, and the position of the isolation region 45 may notnecessarily coincide with that of the electrode isolation region 42.

Hence, hereinafter, the effect of the difference in size between theelectrode isolation region 42 and the isolation region 45 will bedescribed.

For example, when the sensitivity is necessary for the organicphotoelectric conversion film 44 in a fine cell (when the area of theorganic photoelectric conversion film 44 is increased), the width of theisolation region 45 may be set smaller than the width of the electrodeisolation region 42.

In order to avoid the color mixture between pixels and/or tosufficiently increase the resolution, the width of the isolation region45 may be set larger than the width of the electrode isolation region42.

Furthermore, for example, when it is desired to perform pupilcorrection, while the width of the isolation region 45 and that of theelectrode isolation region 42 are set to equal to each other or are setto have a predetermined ratio, the center positions of the respectivewidths may be shifted in a direction from a central pixel to aperipheral pixel located in a chip. Furthermore, in some cases, both thewidths and positions of the isolation region 45 and the electrodeisolation region 42 may be gradually changed and shifted, respectively.

For example, when the isolation region 45 is formed by an ionimplantation method, in order not to do damage to the first electrode 41and/or in order not to mix a secondary sputtered material from the firstelectrode 41 into the organic photoelectric conversion film 44, thewidth and the position of the isolation region 45 may be made tocoincide with those of the electrode isolation region 42. In addition,the position of the isolation region 45 may be made to coincide with theposition of the electrode isolation region 42, and the width of theisolation region 45 may be formed smaller than the width of theelectrode isolation region 42.

A second electrode 47 is formed on the organic photoelectric conversionfilm 44 with the insulating blocking film 46 interposed therebetween.

For the blocking film 46, for example, any material may be used as longas it is transparent in a desired wavelength region of the organicphotoelectric conversion film 44 and has ionization potential (IP)different from that of the second electrode 47 and the organicphotoelectric conversion film 44. For example, for an organicphotoelectric conversion film composed of quinacridone, aluminumquinoline (Alq3) or the like may be effectively used. This blocking film46 is relatively selected in consideration of the work function of theorganic photoelectric conversion film 44 and that of the secondelectrode 47 and is not simply determined by one primary characteristic.For example, an organic SOG or a low dielectric constant film of apolyaryl ether, a polyimide, a fluorinated silicon oxide, a siliconcarbide, or the like may be used to form the blocking film 46. Inaddition, a transparent electrode material forming the second electrode47 or an organic photoelectric conversion material forming the organicphotoelectric conversion film 44 may also be used when conditions aresatisfied.

For the second electrode 47, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

A condenser lens (on-chip lens) 51 condensing incident light on each ofthe photoelectric conversion portions 22 is formed on the secondelectrode 47.

When the condenser lenses 51 are formed, for example, an antireflectionlayer (not shown) may be formed on the surfaces of the condenser lenses51. In addition, an antireflection layer (not shown) may be formedbetween the condenser lenses 51 and the organic photoelectric conversionfilm 44.

As described above, the solid-state image pickup device 1 is formed.

It is assumed that in the solid-state image pickup device 1, forexample, a signal corresponding to green is extracted from the organicphotoelectric conversion film 44, and signals corresponding to blue andred are extracted by bulk spectroscopy. In this case, one example of aplanar arrangement (cording) of the organic photoelectric conversionfilm 44 and the photoelectric conversion portions 22 using the bulkspectroscopy will be described.

As a green dye of the organic photoelectric conversion film 44, forexample, a rhodamine dye, a phthalocyanine derivative, quinacridone,eosin-Y, and a merocyanine dye may be mentioned.

The green of the organic photoelectric conversion film 44 is disposed inevery pixel. In addition, the respective photoelectric conversionportions 22 in which blue and red signals are extracted by the bulkspectroscopy are disposed, for example, in a checkered pattern.Extraction of blue and red signals by the spectroscopy is achieved bythe following principle.

In order to extract blue and red signals by the bulk spectroscopy, thedepth of an N⁻ region 22N and that of a P⁺ region 22P, which form aphotodiode provided in each photoelectric conversion portion 22, aremade different from each other. That is, as for blue, the N⁻ region 22Nis formed in a region close to a light incident side (the depth of lightpenetration is small), so that blue light is preferentiallyphotoelectric-converted. In addition, since the P⁺ region 22P is formedin a deep region, photoelectric conversion of red light is suppressed.On the other hand, as for red, the N⁻ region 22N is formed in a regionfar from the light incident side (the depth of light penetration islarge), so that red light is preferentially photoelectric-converted. Inaddition, in a region close to the light incident side, the deep P⁺region 22P is formed, so that photoelectric conversion of blue light issuppressed. In each pixel, in accordance with the wavelength, the depthof the N⁻ region 22N and the depth of the P⁺ region 22P are preferablyoptimized.

Alternatively, the green of the organic photoelectric conversion film 44is disposed in every pixel. In addition, the photoelectric conversionportions 22 in which blue and red signals are extracted by the bulkspectroscopy are formed in one pixel. The extraction of blue and redsignals by the spectroscopy is achieved by the following principle.

In order to extract blue and red signals by the bulk spectroscopy,although not shown in the figure, the photoelectric conversion portion22 is formed to have a multilayer structure including a first N⁻ region,a P⁺ region, and a second N⁻ region in that order from the lightincident side. That is, blue light is received by a PN junction betweenthe first N⁻ region and the P⁺ region, which is formed in a region closeto the light incident side (the depth of light penetration is small),and is preferentially photoelectric-converted. On the other hand, redlight is received by a PN junction between the P⁺ region and the secondN⁻ region, which is formed in a region far from the light incident side(depth of light penetration is large), and is preferentiallyphotoelectric-converted. The depths of the first N⁻ region, the P⁺region, and the second N⁻ region are each preferably optimized inaccordance with received wavelengths.

By the structure described above, the solid-state image pickup device 1can output separated color signals of green, blue, and red. In addition,since the organic photoelectric conversion film 44 is formed from onlyone layer, lead electrodes (metal films are commonly used) (not shown)and the organic photoelectric conversion film 44 can be advantageouslyeasily machined. In addition, since the bulk spectroscopy is used,damage is no longer done to the organic photoelectric conversion film44. When there is a fear that adhesion between the materials may occur,an isolation layer (not shown) is preferably provided between thelayers.

In the solid-state image pickup device 1, the case in which a greensignal is extracted from the organic photoelectric conversion film 44,and blue and red signals are extracted by the bulk spectroscopy is shownby way of example; however, another combination may also be used.Furthermore, besides the three primary colors, combination amongintermediate colors or arrangement of four colors or more may also beused. In addition, although the case in which the solid-state imagepickup device 1 is applied to a whole-area-open-type CMOS image sensoris shown by way of example, of course, it may also be applied to acommon CMOS image sensor. In addition, the spectroscopy in thephotoelectric conversion portion 22 may also be performed using anorganic color filter layer (not shown). In this case, the organic colorfilter layer may be provided under the organic photoelectric conversionfilm 44 with an optical transparent insulating film interposedtherebetween or may be provided on the organic photoelectric conversionfilm 44 with an insulating film interposed therebetween.

In addition, in the solid-state image pickup device 1, in order toreduce a dark current and white output pixel defects, a film lowering aninterface state and a film having a negative fixed charge (not shown)may be sequentially formed on the surface of the photoelectricconversion portion 22 so as to form a hole accumulation layer at a lightreceiving surface side of the photoelectric conversion portion 22.

The film lowering an interface state is formed, for example, of asilicon oxide (SiO₂) film.

In addition, since the film having a negative fixed charge is formed onthe film lowering an interface state, the hole accumulation layer (notshown) is formed at the light receiving surface side of thephotoelectric conversion portion 22.

Hence, the film lowering an interface level is formed at least on thephotoelectric conversion portion 22 to have a thickness so that the holeaccumulation layer can be formed at the light receiving surface side ofthe photoelectric conversion portion 22 by the film having a negativefixed charge. The thickness is set, for example, to 1 atomic layer to100 nm.

The film having a negative fixed charge is formed, for example, from ahafnium oxide (HfO₂) film, an aluminum oxide (Al₂O₃) film, a zirconiumoxide (ZrO₂) film, a tantalum oxide (Ta₂O₅) film, or a titanium oxide(TiO₂) film. Since the films mentioned above have been actually used,for example, as a gate insulating film of an insulating gate type fieldeffect transistor, film forming methods for the above films are alreadyestablished, and hence the above films can be easily formed.

As the film forming methods, for example, a chemical vapor depositionmethod, a sputtering method, and an atomic layer deposition method maybe mentioned; however, an atomic layer deposition method is preferablyused since a SiO₂ layer lowering an interface state can besimultaneously formed to have a thickness of approximately 1 nm duringthe film formation.

In addition, besides the materials mentioned above, lanthanum oxide(La₂O₃), praseodymium oxide (Pr₂O₃), celium oxide (CeO₂), neodymiumoxide (Nd₂O₃), promethium oxide (Pm₂O₃), samarium oxide (Sm₂O₃),europium oxide (Eu₂O₃), gadolinium oxide (Gd₂O₃), terbium oxide (Tb₂O₃),dysprosium oxide (Dy₂O₃), holmium oxide (Ho₂O₃), erbium oxide (Er₂O₃),thulium oxide (Tm₂O₃), ytterbium oxide (Yb₂O₃), lutetium oxide (Lu₂O₃),and yttrium oxide (Y₂O₃) may also be mentioned.

Furthermore, the film having a negative fixed charge may also be formedfrom a hafnium nitride film, an aluminum nitride film, a hafniumoxynitride film, or an aluminum oxynitride film.

The film having a negative fixed charge may contain silicon (Si) and/ornitrogen (N) as long as the insulating properties are not degraded. Theconcentration thereof is appropriately determined in the range in whichthe insulating properties of the film are not degraded. However, inorder not to generate image defects, such as white spots, additives suchas the silicon and/or nitrogen are preferably added to the surface ofthe film having a negative fixed charge, that is, to a surface oppositeto the active layer 12 side.

As described above, by addition of silicon (Si) and/or nitrogen (N),heat resistance of the film and capability of preventing ionimplantation in the process can be improved.

In addition, as a method for forming the films described above, forexample, a sputtering method, an atomic layer deposition (ALD) method, achemical vapor deposition (CVD) method, or a molecular beam epitaxy(MBE) method may be used.

In the solid-state image pickup device 1, since the isolation region 45performing optical and electrical isolation is formed in the organicphotoelectric conversion film 44 at the position corresponding tobetween the pixels 21, light incident on one pixel is prevented fromdirectly leaking in an adjacent pixel thereto. In addition, carriers(such as electrons e) generated by photoelectrical conversion of lightincident on one pixel is prevented from leaking in an adjacent pixelthereto. That is, the isolation region 45 has an optical isolation(absorption or reflection) function as well as electrical insulatingproperties.

Since the electrode isolation region 42 and the isolation region 45 areformed to be connected to each other, leakage between the electrodeisolation region 42 and the isolation region 45 is prevented, and hencethe effect described above can be further enhanced.

Accordingly, spatial resolution capability can be enhanced, and colormixture can be suppressed, so that a high quality image can be obtainedwith high accuracy.

In addition, since being formed from an impurity region, the isolationregion 45 can be formed, for example, by local ion implantation, andhence, unlike a related technique, etching damage to the organicphotoelectric conversion film 44 is not generated. In addition, thedegree of machining difficulty for forming the isolation region 45 canbe reduced.

[Second Example of Structure of Solid-State Image Pickup Device]

A second example of the structure of a solid-state image pickup devicewill be described using a schematic structural perspectivecross-sectional view and a partial cross-sectional view shown in FIGS.2A and 2B, respectively. In FIGS. 2A and 2B, as one example using thesolid-state image pickup device according to an embodiment of thepresent invention, a whole-area-open-type CMOS image sensor is shown.

As shown in FIGS. 2A and 2B, in a solid-state image pickup device 2, anisolation region 49 corresponding to the isolation region 45 of thesolid-state image pickup device 1 is formed so as to fill an isolationgroove 48 formed in an organic photoelectric conversion film 44.

That is, a plurality of pixels 21 which includes photoelectricconversion portions (such as photodiodes) 22 converting incident lightto electrical signals, transistor groups 23 (some of them are shown inthe figure) composed of MOS transistors, and the like is formed in anactive layer 12 formed of a semiconductor substrate 11. The transistorgroups 23 each include, for example, a transfer transistor, an amplifiertransistor, and a reset transistor. For the semiconductor substrate 11,for example, a silicon substrate is used. Furthermore, a signalprocessing portion (not shown) processing a signal charge read out fromeach of the photoelectric conversion portions 22 is also formed.

Along a part of the periphery of each pixel 21, for example, in a row ora line direction between adjacent pixels 21, an element isolation region24 is formed.

In addition, a wire layer 31 is formed at a front surface side (a lowerside of the semiconductor substrate 11 in the figure) of thesemiconductor substrate 11 in which the photoelectric conversionportions 22 are formed. This wire layer 31 includes wires 32 and aninsulating film 33 covering the wires 32. A support substrate 35 isformed on the wire layer 31. This support substrate 35 is formed, forexample, of a silicon substrate.

Furthermore, in the solid-state image pickup device 2, an insulatingfilm (not shown) having an optical transparency is formed at a rearsurface side of the semiconductor substrate 11. In addition, on thisinsulating film (an upper surface side in the figure), first electrodes41 are formed.

For the first electrode 41, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

In addition, an electrode isolation region 42 is formed between thefirst electrodes 41 so as to correspond to between the pixels 21. Thatis, the first electrodes 41 are independently formed to correspond tothe respective pixels. In addition, the surface of each of the firstelectrodes 41 and the surface of the electrode isolation region 42 arepreferably planarized to be flush with each other.

Furthermore, the organic photoelectric conversion film 44 is formed onthe first electrodes 41 and the electrode isolation region 42.

In addition, depending on the difference in ionization potential betweenthe first electrode 41 and the organic photoelectric conversion film 44,a blocking film (not shown) similar to a blocking film 46 which will bedescribed later may be necessary between the first electrodes 41 and theorganic photoelectric conversion film 44 in some cases.

The organic photoelectric conversion film 44 is formed, for example, tohave a thickness of 100 nm. This thickness may be optionally selected.As this organic photoelectric conversion film 44, for example, polymersof phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole,pycoline, thiophene, acetylene and diacetylene or derivatives thereofmay be used.

Furthermore, for example, there can be preferably used metal complexdyes, cyanine-based dyes, merocyanine-based dyes, phenylxanthene-baseddyes, triphenylmethane-based dyes, rhodacyanine-based dyes,xanthene-based dyes, macrocyclic aza-annulene-based dyes, azulene-baseddyes, naphtoquinone-based dyes, anthraquinone-based dyes, chaincompounds obtained by condensation between condensed polycyclic aromaticcompounds, such as anthracene and pyrene, and aromatic or hetero ringcompounds, two nitrogen-containing heterocyclic rings, such asquinoline, benzothiazole, and benzooxazole, bonded through a squaryliumgroup and/or a croconic methine group, and cyanine analogue dyes bondedby a squarylium group and/or a croconic methine group.

In addition, as the metal complex dyes, dithiol metal complex dyes,metal phthalocyanine dyes, metal porphyrin dyes or ruthenium complexdyes are preferable, and the ruthenium complex dyes are particularlypreferable; however, the metal complex dyes are not limited to thosementioned above.

Furthermore, the isolation groove 48 is formed in the organicphotoelectric conversion film 44 at a position corresponding to betweenthe pixels 21, and the isolation region 49 is formed so as to fill thisisolation groove 48. Hence, the isolation region 49 is formed alongupper side peripheries of the pixels 21. This isolation region 49 is aregion which has insulating properties and which reflects or absorbsincident light. Hence, the above organic photoelectric conversion film44 is divided to correspond to the respective pixels.

In this solid-state image pickup device, as one example, the insulatingblocking film 46 formed on the organic photoelectric conversion film 44is buried. That is, the blocking film 46 is formed on the organicphotoelectric conversion film 44 and is partially formed in theisolation groove 48, and as a result, the isolation region 49 is formedfrom the blocking film 46 buried in the groove 48.

Furthermore, a second electrode 47 is formed on the blocking film 46.

For the blocking film 46, for example, any material may be used as longas it is transparent in a desired wavelength region of the organicphotoelectric conversion film 44 and has ionization potential (IP)different from that of the second electrode 47 and the organicphotoelectric conversion film 44. For example, for an organicphotoelectric conversion film composed of quinacridone, aluminumquinoline (Alq3) or the like is effectively used. This blocking film 46is relatively selected in consideration of the work function of theorganic photoelectric conversion film 44 and that of the secondelectrode 47 and is not simply determined by one primary characteristic.For example, an organic SOG or a low dielectric constant film of apolyaryl ether, a polyimide, a fluorinated silicon oxide, a siliconcarbide, or the like may be used to form the blocking film 46. Inaddition, a transparent electrode material forming the second electrode47 or an organic photoelectric conversion material forming the organicphotoelectric conversion film 44 may also be used when conditions aresatisfied.

For the second electrode 47, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

A condenser lens (on-chip lens) 51 condensing incident light on each ofthe photoelectric conversion portions 22 is formed on the secondelectrode 47.

When the condenser lenses 51 are formed, for example, an antireflectionlayer (not shown) may be formed on the surfaces of the condenser lenses51. In addition, an antireflection layer (not shown) may be formedbetween the condenser lenses 51 and the organic photoelectric conversionfilm 44.

As described above, the solid-state image pickup device 2 is formed.

The organic photoelectric conversion film 44 may be formed of aphotosensitive material, such as a photosensitive organic photoelectricconversion material. The photosensitivity thereof may be either apositive type or a negative type.

As the photosensitive organic photoelectric conversion material, aphotosensitive material may be mixed with the aforementioned organicphotoelectric conversion material, or a photosensitive functional groupmay be imparted to an organic photoelectric conversion material itself.As the photosensitive material or the photosensitive functional group,for example, an azido compound-based, a diazonaphtoquinonenovolac-based, a chemical amplification-based, and an opticalamplification-based material or group, each of which is generally knownin a lithographic technique field, may be mentioned and may be selectedin consideration of matching with an organic photoelectric conversionmaterial.

As described above, since the organic photoelectric conversion film 44has photosensitivity, after the organic photoelectric conversion film 44is formed, when exposure and development processes are performedthereon, the isolation groove 48 can be formed. Since the aboveisolation groove 48 is formed by the exposure and development processesas described above, unlike a related technique, etching damage is notdone to the organic photoelectric conversion film 44. Whenevernecessary, before and/or after the exposure and/or the developmentprocess, an appropriate baking treatment is performed.

In addition, as a material forming the isolation region 49, any materialmay be used as long as it has an electrical isolation function(insulating properties) and an optical isolation (absorption orreflection) function.

For example, a material different from that forming the blocking film 46may be used for forming the isolation region 49.

For example, the isolation region 49 may be formed using a carbon blackresist having photosensitivity. An isolation region 49 formed from acarbon black resist has insulating properties and also has an opticalisolation function caused by optical absorption of contained carbon.

In addition, although the isolation region 49 is formed to coincide withthe electrode isolation region 42, as for the relative relationshipbetween the width of the isolation region 49 and the width of theelectrode isolation region 42, the widths thereof may not be necessarilyequal to each other, and the position of the isolation region 49 may notnecessarily coincide with that of the electrode isolation region 42. Theeffect of the difference in size between the electrode isolation region42 and the isolation region 49 is the same as described above.

In addition, the isolation region 49 may also be formed in the blockingfilm 46 formed on the organic photoelectric conversion film 44 at aposition corresponding to between the pixels.

In the solid-state image pickup device 2, the case in which a greensignal is extracted from the organic photoelectric conversion film 44,and blue and red signals are extracted by the bulk spectroscopy is shownby way of example; however, another combination may also be used.Furthermore, besides the three primary colors, combination amongintermediate colors or arrangement of four colors or more may also beused. In addition, although the case in which the solid-state imagepickup device 2 is applied to a whole-area-open-type CMOS image sensoris shown by way of example, of course, it may also be applied to acommon CMOS image sensor. In addition, the spectroscopy in thephotoelectric conversion portion 22 may also be performed using anorganic color filter layer (not shown). In this case, the organic colorfilter layer may be provided under the organic photoelectric conversionfilm 44 with an optical transparent insulating film interposedtherebetween or may be provided on the organic photoelectric conversionfilm 44 with an insulating film interposed therebetween.

In addition, in the solid-state image pickup device 2, as in the case ofthe solid-state image pickup device 1, a film lowering an interfacestate and a film having a negative fixed charge (not shown) may besequentially formed on the surface of the photoelectric conversionportion 22 so as to form a hole accumulation layer at a light receivingsurface side of the photoelectric conversion portion 22. As describedabove, when the hole accumulation layer is formed at the light receivingsurface side of the photoelectric conversion portion 22, a dark currentand/or white output pixel defects can be reduced.

In the solid-state image pickup device 2, since the isolation region 49performing optical and electrical isolation is formed in the organicphotoelectric conversion film 44 at the position corresponding tobetween the pixels 21, light incident on one pixel is prevented fromdirectly leaking in an adjacent pixel thereto. In addition, carriers(such as electrons e) generated by photoelectrical conversion of lightincident on one pixel is prevented from leaking in an adjacent pixelthereto. That is, the isolation region 49 has an optical isolation(absorption or reflection) function as well as electrical insulatingproperties.

Since the electrode isolation region 42 and the isolation region 49 areformed to be connected to each other, leakage between the electrodeisolation region 42 and the isolation region 49 is prevented, and hencethe effect described above can be further enhanced.

Accordingly, the spatial resolution capability can be enhanced, and thecolor mixture can be suppressed, so that a high quality image can beobtained with high accuracy.

In addition, since the isolation groove 48 can be formed using exposureand development processes, unlike a related technique, etching damage tothe organic photoelectric conversion film 44 is not generated. Inaddition, the degree of machining difficulty for forming the isolationregion 49 can be reduced.

[Third and Fourth Examples of Structure of Solid-State Image PickupDevice]

A third and a fourth example of the structure of a solid-state imagepickup device will be described using schematic structuralcross-sectional views in FIGS. 3A and 3B, respectively, each of whichshows an important portion.

In FIGS. 3A and 3B, as one example using the solid-state image pickupdevice according to an embodiment of the present invention, awhole-area-open-type CMOS image sensor is shown.

[Third Example of Structure of Solid-State Image Pickup Device]

As shown in FIG. 3A, as in the case of the solid-state image pickupdevice 1, in a solid-state image pickup device 3, first electrodes 41,an organic photoelectric conversion film 44, a blocking film 46, and asecond electrode 47, which are a first layer group, are formed on anactive layer 12 of a semiconductor substrate 11. An electrode isolationregion 42 separating the first electrodes 41 for respective pixels isformed between the first electrodes 41, and an isolation region 45dividing the organic photoelectric conversion film 44 for each pixel isformed therein.

In addition, first electrodes 61, an organic photoelectric conversionfilm 64, a blocking film 66, and a second electrode 67, which are asecond layer group, are formed on the second electrode 47 with aninsulating film 60 interposed therebetween. An electrode isolationregion 62 separating the first electrodes 61 for the respective pixelsis formed between the first electrodes 41, and an isolation region 65dividing the organic photoelectric conversion film 64 for each pixel isformed therein.

In this solid-state image pickup device 3, contact portions 81 and 82with insulating films 84 and 85 provided therearound, respectively, areformed from the active layer 12 side so as to be connected to the firstelectrodes 41 and 61, respectively.

In addition, depending on the difference in ionization potential betweenthe first electrode layer 41 and the organic photoelectric conversionfilm 44, a blocking film (not shown) similar to the blocking film 46described above may be necessary in some cases between the firstelectrodes 41 and the organic photoelectric conversion film 44. As inthe case described above, depending on the difference in ionizationpotential between the first electrode layer 61 and the organicphotoelectric conversion film 64, a blocking film (not shown) similar tothe blocking film 66 described above may be necessary in some casesbetween the first electrodes 61 and the organic photoelectric conversionfilm 64.

[Fourth Example of Structure of Solid-State Image Pickup Device]

As shown in FIG. 3B, as in the case of the solid-state image pickupdevice 3, in a solid-state image pickup device 4, first electrodes 41,an organic photoelectric conversion film 44, a blocking film 46, and asecond electrode 47, which are a first layer group, are formed on anactive layer 12 of a semiconductor substrate 11. An electrode isolationregion 42 separating the first electrodes 41 for respective pixels isformed between the first electrodes 41, and an isolation region 45dividing the organic photoelectric conversion film 44 for each pixel isformed therein.

In addition, first electrodes 61, an organic photoelectric conversionfilm 64, a blocking film 66, and a second electrode 67, which are asecond layer group, are formed on the second electrode 47 with aninsulating film 60 interposed therebetween. An electrode isolationregion 62 separating the first electrodes 61 for the respective pixelsis formed between the first electrodes 61, and an isolation region 65dividing the organic photoelectric conversion film 64 for each pixel isformed therein.

Furthermore, first electrodes 71, an organic photoelectric conversionfilm 74, a blocking film 76, and a second electrode 77, which are athird layer group, are formed on the second electrode 67 with aninsulating film 70 interposed therebetween. An electrode isolationregion 72 separating the first electrodes 71 for the respective pixelsis formed between the first electrodes 71, and an isolation region 75dividing the organic photoelectric conversion film 74 for each pixel isformed therein.

In this solid-state image pickup device 4, contact portions 81, 82, and83 with insulating films 84, 85, and 86 provided therearound,respectively, are formed from the active layer 12 side so as to beconnected to the first electrodes 41, 61, and 71, respectively.

In addition, depending on the difference in ionization potential betweenthe first electrode 41 and the organic photoelectric conversion film 44,a blocking film (not shown) similar to the blocking film 46 describedabove may be necessary in some cases between the first electrodes 41 andthe organic photoelectric conversion film 44. As in the case describedabove, depending on the difference in ionization potential between thefirst electrode layer 61 and the organic photoelectric conversion film64, a blocking film (not shown) similar to the blocking film 66described above may be necessary in some cases between the firstelectrodes 61 and the organic photoelectric conversion film 64.Furthermore, as in the case described above, depending on the differencein ionization potential between the first electrode layer 71 and theorganic photoelectric conversion film 74, a blocking film (not shown)similar to the blocking film 76 described above may be necessary in somecases between the first electrodes 71 and the organic photoelectricconversion film 74.

[Fifth and Sixth Examples of Structure of Solid-State Image PickupDevice]

Next, a fifth and a sixth example of the structure of a solid-stateimage pickup device will be described using schematic structuralcross-sectional views in FIGS. 4A and 4B, respectively, each of whichshows an important portion.

In FIGS. 4A and 4B, as one example using the solid-state image pickupdevice according to an embodiment of the present invention, awhole-area-open-type CMOS image sensor is shown.

[Fifth Example of Structure of Solid-State Image Pickup Device]

As shown in FIG. 4A, as in the case of the solid-state image pickupdevice 2, in a solid-state image pickup device 5, first electrodes 41,an organic photoelectric conversion film 44, a blocking film 46, and asecond electrode 47, which are a first layer group, are formed on anactive layer 12 of a semiconductor substrate 11. An electrode isolationregion 42 separating the first electrodes 41 for respective pixels isformed between the first electrodes 41, and an isolation region 49dividing the organic photoelectric conversion film 44 for each pixel isformed therein.

In addition, first electrodes 61, an organic photoelectric conversionfilm 64, a blocking film 66, and a second electrode 67, which are asecond layer group, are formed on the second electrode 47 with aninsulating film 60 interposed therebetween. An electrode isolationregion 62 separating the first electrodes 61 for the respective pixelsis formed between the first electrodes 41, and an isolation region 69dividing the organic photoelectric conversion film 64 for each pixel isformed therein.

In this solid-state image pickup device 5, contact portions 81 and 82with insulating films 84 and 85 provided therearound, respectively, areformed from the active layer 12 side so as to be connected to the firstelectrodes 41 and 61, respectively.

In addition, depending on the difference in ionization potential betweenthe first electrode layer 41 and the organic photoelectric conversionfilm 44, a blocking film (not shown) similar to the blocking film 46described above may be necessary in some cases between the firstelectrodes 41 and the organic photoelectric conversion film 44. As inthe case described above, depending on the difference in ionizationpotential between the first electrode layer 61 and the organicphotoelectric conversion film 64, a blocking film (not shown) similar tothe blocking film 66 described above may be necessary in some casesbetween the first electrodes 61 and the organic photoelectric conversionfilm 64.

[Sixth Example of Structure of Solid-State Image Pickup Device]

As shown in FIG. 4B, as in the case of the solid-state image pickupdevice 5, in a solid-state image pickup device 6, first electrodes 41,an organic photoelectric conversion film 44, a blocking film 46, and asecond electrode 47, which are a first layer group, are formed on anactive layer 12 of a semiconductor substrate 11. An electrode isolationregion 42 separating the first electrodes 41 for respective pixels isformed between the first electrodes 41, and an isolation region 49dividing the organic photoelectric conversion film 44 for each pixel isformed therein.

In addition, first electrodes 61, an organic photoelectric conversionfilm 64, a blocking film 66, and a second electrode 67, which are asecond layer group, are formed on the second electrode 47 with aninsulating film 60 interposed therebetween. An electrode isolationregion 62 separating the first electrodes 61 for the respective pixelsis formed between the first electrodes 61, and an isolation region 69dividing the organic photoelectric conversion film 64 for each pixel isformed therein.

Furthermore, first electrodes 71, an organic photoelectric conversionfilm 74, a blocking film 76, and a second electrode 77, which are athird layer group, are formed on the second electrode 67 with aninsulating film 70 interposed therebetween. An electrode isolationregion 72 separating the first electrodes 71 for the respective pixelsis formed between the first electrodes 71, and an isolation region 79dividing the organic photoelectric conversion film 74 for each pixel isformed therein.

In this solid-state image pickup device 6, contact portions 81, 82, and83 with insulating films 84, 85, and 86 provided therearound,respectively, are formed from the active layer 12 side so as to beconnected to the first electrodes 41, 61, and 71, respectively.

In addition, depending on the difference in ionization potential betweenthe first electrode 41 and the organic photoelectric conversion film 44,a blocking film (not shown) similar to the blocking film 46 describedabove may be necessary in some cases between the first electrodes 41 andthe organic photoelectric conversion film 44. As in the case describedabove, depending on the difference in ionization potential between thefirst electrode layer 61 and the organic photoelectric conversion film64, a blocking film (not shown) similar to the blocking film 66described above may be necessary in some cases between the firstelectrodes 61 and the organic photoelectric conversion film 64.Furthermore, as in the case described above, depending on the differencein ionization potential between the first electrode layer 71 and theorganic photoelectric conversion film 74, a blocking film (not shown)similar to the blocking film 76 described above may be necessary in somecases between the first electrodes 71 and the organic photoelectricconversion film 74.

As described above, at least two organic photoelectric conversion filmsmay be provided. In this case, the number of colors extracted by thebulk spectroscopy of the photoelectric conversion portion 22 may beeither one or two. For example, it may be even possible that two colorsare extracted by the bulk spectroscopy and three colors are extractedusing the organic photoelectric conversion films.

2. Second Embodiment

[First Example of Method for Manufacturing Solid-State Image PickupDevice]

Next, a first example of a method for manufacturing a solid-state imagepickup device according to a second embodiment of the present inventionwill be described with reference to manufacturing processcross-sectional views shown in FIGS. 5A to 6B. This manufacturing methodis one example of a method for manufacturing the above-describedsolid-state image pickup device 1. In addition, constituent elements aredesignated by the same reference numerals as those of the solid-stateimage pickup device 1 described with reference to FIGS. 1A and 1B.

First, although not shown in the figure, by a common manufacturingmethod, a plurality of pixels 21 having, for example, photoelectricconversion portions (such as photodiodes) 22 converting incident lightinto electrical signals and transistor groups 23 (some of them are shownin the figure) each including a transfer transistor, an amplifiertransistor, a reset transistor, and the like is formed in an activelayer 12 (see FIG. 5A) formed of a semiconductor substrate 11. For thesemiconductor substrate 11, for example, a silicon substrate is used.Furthermore, a signal processing portion (not shown) processing a signalcharge read out from each of the photoelectric conversion portions 22 isalso formed.

Along a part of the periphery of each pixel 21, for example, in a row ora line direction between adjacent pixels 21, an element isolation region24 is formed.

In addition, a wire layer 31 is formed at a front surface side (a lowerside of the semiconductor substrate 11 in the figure) of thesemiconductor substrate 11 in which the photoelectric conversionportions 22 are formed. This wire layer 31 includes wires 32 and aninsulating film 33 covering the wires 32. A support substrate 35 isformed on the wire layer 31. This support substrate 35 is formed, forexample, of a silicon substrate.

Furthermore, an insulating film (not shown) having an opticaltransparency is formed at a rear surface side of the semiconductorsubstrate 11. In addition, on this insulating film (an upper surfaceside in the figure), first electrodes 41 are formed.

For the first electrode 41, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

In addition, as shown in FIG. 5A, an electrode isolation region 42 isformed between the first electrodes 41 so as to correspond to betweenthe pixels 21. That is, the first electrodes 41 are separated tocorrespond to the respective pixels. The electrode isolation region 42is formed in such a way that after an insulating film is formed to burythe first electrodes 41, the surface of the insulating film isplanarized to expose the surfaces of the first electrodes 41. For thisinsulating film, an insulating film used for a common semiconductordevice is used. For example, a silicon oxide film is used.

Next, an organic photoelectric conversion film 44 is formed on the firstelectrodes 41 and the electrode isolation region 42. The organicphotoelectric conversion film 44 is formed, for example, to have athickness of 100 nm. This thickness may be optionally selected. As thisorganic photoelectric conversion film 44, for example, polymers ofphenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole,pycoline, thiophene, acetylene and diacetylene or derivatives thereofmay be used.

Furthermore, for example, there can be preferably used metal complexdyes, cyanine-based dyes, merocyanine-based dyes, phenylxanthene-baseddyes, triphenylmethane-based dyes, rhodacyanine-based dyes,xanthene-based dyes, macrocyclic aza-annulene-based dyes, azulene-baseddyes, naphtoquinone-based dyes, anthraquinone-based dyes, chaincompounds obtained by condensation between condensed polycyclic aromaticcompounds, such as anthracene and pyrene, and aromatic or hetero ringcompounds, two nitrogen-containing heterocyclic rings, such asquinoline, benzothiazole, and benzooxazole, bonded through a squaryliumgroup and/or a croconic methine group, and cyanine analogue dyes bondedby a squarylium group and/or a croconic methine group.

In addition, as the metal complex dyes, dithiol metal complex dyes,metal phthalocyanine dyes, metal porphyrin dyes or ruthenium complexdyes are preferable, and the ruthenium complex dyes are particularlypreferable; however, the metal complex dyes are not limited to thosementioned above.

Next, as shown in FIG. 5B, after a resist film 91 is formed on theorganic photoelectric conversion film 44, an opening portion 92 isformed in the resist film 91 by a lithography technique, such asexposure and development. This opening portion 92 is formed in theorganic photoelectric conversion film 44 to correspond to between thepixels.

As a photoresist used for the resist film 91, a material used for acommon semiconductor process may be used, and a resist strippable froman organic photoelectric conversion material may be used. As the aboveresist, for example, an azido compound resist, adiazonaphthoquinone-novolac resist, a chemical amplification resist, andan optical amplification resist may be mentioned.

Next, as shown in FIG. 5C, by an ion implantation method using theresist film 91 as an ion implantation mask, an impurity is implanted inthe organic photoelectric conversion film 44 at a position correspondingto between the pixels 21 to form an isolation region 45. Hence, theisolation region 45 is formed along upper peripheral portions of thepixels. That is, the organic photoelectric conversion film 44 is dividedfor each pixel by the isolation region 45. As the impurity, there isselected an impurity forming an impurity region used as an isolationregion 45 which has insulating properties and which reflects or absorbsincident light. For example, an impurity, such as nitrogen (N) or oxygen(O), is implanted in the organic photoelectric conversion film 44, forexample, at a dose of 1×10¹¹ cm⁻² or more.

As an impurity forming an isolation region 45 which optically absorbslight, for example, carbon (C), oxygen (O), and nitrogen (N) may bementioned, and when at least one of these impurities is implanted, anabsorption layer in which bond absorption of an organic compound occurscan be formed.

As an impurity forming an isolation region 45 which optically reflectslight, for example, hydrogen (H), helium (He), oxygen (O), and nitrogen(N) may be mentioned, and when at least one of these impurities isimplanted, an isolation region 45 having a low refractive index comparedto that of the organic photoelectric conversion film 44 is formed.Hence, optical reflection occurs at an interface between the organicphotoelectric conversion film 44 and the isolation region 45. Inaddition, in order to form an interface at which optical reflectionoccurs, the impurity concentration distribution is preferably made assteep as possible. In addition, as the impurity forming an isolationregion 45 which optically reflects light, a metal ion element, such astitanium (Ti), zirconium (Zr), hafnium (Hf), or tungsten (W), having ahigh reflectance may also be mentioned.

Next, among impurities which impart electrical insulating properties,there is an impurity which is turned into an electrically insulatingmaterial when being implanted in the organic photoelectric conversionfilm 44, and for example, oxygen (O) and nitrogen (N) may be mentioned.

Among the impurities mentioned above, an impurity which forms a regioncapable of performing optical isolation (absorption or reflection) inthe organic photoelectric conversion film 44 and an impurity which formsa region having electrical insulating properties therein may beselected. As an impurity which can achieve the above-described twofunctions, for example, oxygen (O) and nitrogen (N) may be mentioned.

In addition, when an impurity which forms an isolation region impartingoptical absorption or reflection properties and an impurity which formsan isolation region imparting electrical isolation properties are bothimplanted in the organic photoelectric conversion film 44, an isolationregion 45 performing optical and electrical isolation can also beformed.

In addition, the isolation region 45 may be formed by breaking bonds,such as molecular bonds, of an organic photoelectric conversion materialin the organic photoelectric conversion film 44. For example, whenhelium (He), argon (Ar), nitrogen (N), oxygen (O), or the like ision-implanted at a high dose in the organic photoelectric conversionfilm 44, damage is done to bonds between molecules and/or atoms (forexample, molecular bonds are broken thereby). As a result, the isolationregion 45 is formed. The high dose is a dose, for example, at which themolecular bonds in the organic photoelectric conversion film 44 arebroken, and although depending on the type of organic photoelectricconversion film 44, ion implantation is performed, for example, at adose of 1×10¹⁴ cm⁻² or more.

In addition, in the isolation region 45 formed by ion-implantation of animpurity in the organic photoelectric conversion film 44, some impuritythus implanted may show the above optical and/or insulating properties,and some impurity may form a compound showing the above properties inthe organic photoelectric conversion film 44.

In addition, although the isolation region 45 is formed to coincide withthe electrode isolation region 42, as for the relative relationshipbetween the width of the isolation region 45 and the width of theelectrode isolation region 42, the widths thereof may not be necessarilyequal to each other, and the position of the isolation region 45 may notnecessarily coincide with that of the electrode isolation region 42. Forexample, in order not to do damage to the first electrode 41 byimplanted ions and/or in order not to mix a secondary sputtered materialfrom the first electrode 41 into the organic photoelectric conversionfilm 44, the position of the implanted region is preferably made tocoincide with that of the electrode isolation region 42, and the widthof the implanted region is preferably formed smaller than that of theelectrode isolation region 42.

In addition, the effect of the difference in size between the electrodeisolation region 42 and the isolation region 45 is the same as describedin the first example of the solid-state image pickup device 1.

Next, the resist film 91 is removed, and as shown in FIG. 6A, thesurface of the organic photoelectric conversion film 44 is exposed.

Next, as shown in FIG. 6B, on the organic photoelectric conversion film44, a second electrode 47 is formed with an insulating blocking film 46interposed therebetween.

For the blocking film 46, for example, any material may be used as longas it is transparent in a desired wavelength region of the organicphotoelectric conversion film 44 and has ionization potential (IP)different from that of the second electrode 47 and the organicphotoelectric conversion film 44. For example, for an organicphotoelectric conversion film composed of quinacridone, aluminumquinoline (Alq3) or the like is effectively used. This blocking film 46is relatively selected in consideration of the work function of theorganic photoelectric conversion film 44 and that of the secondelectrode 47 and is not simply determined by one primary characteristic.For example, an organic SOG or a low dielectric constant film of apolyaryl ether, a polyimide, a fluorinated silicon oxide, a siliconcarbide, or the like may be used to form the blocking film 46. Inaddition, a transparent electrode material forming the second electrode47 or an organic photoelectric conversion material forming the organicphotoelectric conversion film 44 may also be used when conditions aresatisfied.

In addition, depending on the difference in ionization potential betweenthe first electrode 41 and the organic photoelectric conversion film 44,a blocking film (not shown) similar to the blocking film 46 describedabove may be necessary between the first electrodes 41 and the organicphotoelectric conversion film 44 in some cases.

For the second electrode 47, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

Although not shown in the figure, a condenser lens (on-chip lens) 51condensing incident light on each of the photoelectric conversionportions 22 is formed on the second electrode 47.

When the condenser lenses 51 are formed, for example, an antireflectionlayer (not shown) may be formed on the surfaces of the condenser lenses51. In addition, an antireflection layer (not shown) may be formedbetween the condenser lenses 51 and the organic photoelectric conversionfilm 44.

As described above, the solid-state image pickup device 1 is formed.

In the method for manufacturing the solid-state image pickup device 1, amanufacturing method in which a green signal is extracted from theorganic photoelectric conversion film 44, and blue and red signals areextracted by the bulk spectroscopy is shown; however, anothercombination may also be used. Furthermore, besides the three primarycolors, combination among intermediate colors or arrangement of fourcolors or more may also be used. In addition, although the case in whichthe solid-state image pickup device 1 is applied to awhole-area-open-type CMOS image sensor is shown by way of example, ofcourse, it may also be applied to a common CMOS image sensor. Inaddition, the spectroscopy in the photoelectric conversion portion 22may also be performed using an organic color filter layer (not shown).In this case, the organic color filter layer may be provided under theorganic photoelectric conversion film 44 with an optical transparentinsulating film interposed therebetween or may be provided on theorganic photoelectric conversion film 44 with an insulating filminterposed therebetween.

In addition, in the solid-state image pickup device 1, in order toreduce a dark current and white output pixel defects, a film lowering aninterface state and a film having a negative fixed charge (not shown)may be sequentially formed on the surface of the photoelectricconversion portion 22 so as to form a hole accumulation layer at a lightreceiving surface side of the photoelectric conversion portion 22.

The film lowering an interface state is formed, for example, of asilicon oxide (SiO₂) film.

In addition, since the film having a negative fixed charge is formed onthe film lowering an interface state, the hole accumulation layer (notshown) is formed at the light receiving surface side of thephotoelectric conversion portion 22.

Hence, the film lowering an interface state is formed at least on thephotoelectric conversion portion 22 to have a thickness so that the holeaccumulation layer can be formed at the light receiving surface side ofthe photoelectric conversion portion 22 by the film having a negativefixed charge. The thickness is set, for example, to 1 atomic layer to100 nm.

The film having a negative fixed charge is formed, for example, from ahafnium oxide (HfO₂) film, an aluminum oxide (Al₂O₃) film, a zirconiumoxide (ZrO₂) film, a tantalum oxide (Ta₂O₅) film, or a titanium oxide(TiO₂) film. Since the films mentioned above have been actually used,for example, as a gate insulating film of an insulating gate type fieldeffect transistor, film forming methods for the above films are alreadyestablished, and hence the above films can be easily formed.

As the film forming methods, for example, a chemical vapor depositionmethod, a sputtering method, and an atomic layer deposition method maybe mentioned; however, an atomic layer deposition method is preferablyused since a SiO₂ layer lowering an interface state can besimultaneously formed to have a thickness of approximately 1 nm duringthe film formation.

In addition, besides the materials mentioned above, lanthanum oxide(La₂O₃), praseodymium oxide (Pr₂O₃), celium oxide (CeO₂), neodymiumoxide (Nd₂O₃), promethium oxide (Pm₂O₃), samarium oxide (Sm₂O₃),europium oxide (Eu₂O₃), gadolinium oxide (Gd₂O₃), terbium oxide (Tb₂O₃),dysprosium oxide (Dy₂O₃), holmium oxide (Ho₂O₃), erbium oxide (Er₂O₃),thulium oxide (Tm₂O₃), ytterbium oxide (Yb₂O₃), lutetium oxide (Lu₂O₃),and yttrium oxide (Y₂O₃) may also be mentioned.

Furthermore, the film having a negative fixed charge may also be formedfrom a hafnium nitride film, an aluminum nitride film, a hafniumoxynitride film, or an aluminum oxynitride film.

The film having a negative fixed charge may contain silicon (Si) and/ornitrogen (N) as long as the insulating properties are not degraded. Theconcentration thereof is appropriately determined in the range in whichthe insulating properties of the film are not degraded. However, inorder not to generate image defects, such as white spots, additives suchas the silicon and/or nitrogen are preferably added to the surface ofthe film having a negative fixed charge, that is, to a surface oppositeto the active layer 12 side.

As described above, by addition of silicon (Si) and/or nitrogen (N),heat resistance of the film and capability of preventing ionimplantation in the process can be improved.

In addition, as a method for forming the films described above, forexample, a sputtering method, an atomic layer deposition (ALD) method, achemical vapor deposition (CVD) method, or a molecular beam epitaxy(MBE) method may be used.

In the method for manufacturing a solid-state image pickup device (firstexample), since the isolation region 45 performing optical andelectrical isolation is formed in the organic photoelectric conversionfilm 44 at the position corresponding to between the pixels 21, lightincident on one pixel is prevented from directly leaking in an adjacentpixel thereto. In addition, carriers (such as electrons e) generated byphotoelectrical conversion of light incident on one pixel is preventedfrom leaking in an adjacent pixel thereto. That is, the isolation region45 has an optical isolation (absorption or reflection) function as wellas electrical insulating properties.

Since the electrode isolation region 42 and the isolation region 45 areformed to be connected to each other, leakage between the electrodeisolation region 42 and the isolation region 45 is prevented, and hencethe effect described above can be further enhanced.

Accordingly, the spatial resolution capability can be enhanced, and thecolor mixture can be suppressed, so that a high quality image can beobtained with high accuracy.

In addition, since being formed from an impurity region, the isolationregion 45 can be formed, for example, by local ion implantation, andhence, unlike a related technique, etching damage to the organicphotoelectric conversion film 44 is not generated. In addition, thedegree of machining difficulty for forming the isolation region 45 canbe reduced.

[Second Example of Method for Manufacturing Solid-State Image PickupDevice]

Next, a second example of the method for manufacturing a solid-stateimage pickup device according to the second embodiment of the presentinvention will be described with reference to manufacturing processcross-sectional views shown in FIGS. 7A to 7D. This manufacturing methodis one example of a method for manufacturing the above-describedsolid-state image pickup device 2. In addition, constituent elements aredesignated by the same reference numerals as those of the solid-stateimage pickup device 2 described with reference to FIGS. 2A and 2B.

First, although not shown in the figure, by a common manufacturingmethod, a plurality of pixels 21 having, for example, photoelectricconversion portions (such as photodiodes) 22 converting incident lightinto electrical signals and transistor groups 23 (some of them are shownin the figure) each including a transfer transistor, an amplifiertransistor, a reset transistor, and the like is formed in an activelayer 12 (see FIG. 7A) formed of a semiconductor substrate 11. For thesemiconductor substrate 11, for example, a silicon substrate is used.Furthermore, a signal processing portion (not shown) processing a signalcharge read out from each of the photoelectric conversion portions 22 isalso formed.

Along a part of the periphery of each pixel 21, for example, in a row ora line direction between adjacent pixels 21, an element isolation region24 is formed.

In addition, a wire layer 31 is formed at a front surface side (a lowerside of the semiconductor substrate 11 in the figure) of thesemiconductor substrate 11 in which the photoelectric conversionportions 22 are formed. This wire layer 31 includes wires 32 and aninsulating film 33 covering the wires 32. A support substrate 35 isformed on the wire layer 31. This support substrate 35 is formed, forexample, of a silicon substrate.

Furthermore, an insulating film (not shown) having an opticaltransparency is formed at a rear surface side of the semiconductorsubstrate 11. In addition, on this insulating film (an upper surfaceside in the figure), first electrodes 41 are formed.

For the first electrode 41, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

In addition, an electrode isolation region 42 is formed between thefirst electrodes 41 so as to correspond to between the pixels 21. Thatis, the first electrodes 41 are separated to correspond to therespective pixels.

Next, as shown in FIG. 7A, an organic photoelectric conversion film 44is formed on the first electrodes 41 with an insulating film (not shown)having a planarized surface interposed therebetween. The organicphotoelectric conversion film 44 is formed, for example, to have athickness of 100 nm. This thickness may be optionally selected.

The organic photoelectric conversion film 44 is formed of aphotosensitive material, such as a photosensitive organic photoelectricconversion material. The sensitivity thereof may be either a positivetype or a negative type.

As the photosensitive organic photoelectric conversion material, aphotosensitive material may be mixed with the aforementioned organicphotoelectric conversion material, or a photosensitive functional groupmay be imparted to an organic photoelectric conversion material itself.As the photosensitive material or the photosensitive functional group,for example, an azido compound-based, a diazonaphtoquinonenovolac-based, a chemical amplification-based, and an opticalamplification-based material or group, each of which is generally knownin a lithographic technique field, may be mentioned and may be selectedin consideration of matching with an organic photoelectric conversionmaterial.

As the organic photoelectric conversion material, for example, polymersof phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole,pycoline, thiophene, acetylene and diacetylene or derivatives thereofmay be used.

Furthermore, for example, there can be preferably used metal complexdyes, cyanine-based dyes, merocyanine-based dyes, phenylxanthene-baseddyes, triphenylmethane-based dyes, rhodacyanine-based dyes,xanthene-based dyes, macrocyclic aza-annulene-based dyes, azulene-baseddyes, naphtoquinone-based dyes, anthraquinone-based dyes, chaincompounds obtained by condensation between condensed polycyclic aromaticcompounds, such as anthracene and pyrene, and aromatic or hetero ringcompounds, two nitrogen-containing heterocyclic rings, such asquinoline, benzothiazole, and benzooxazole, bonded through a squaryliumgroup and/or a croconic methine group, and cyanine analogue dyes bondedby a squarylium group and/or a croconic methine group.

In addition, as the metal complex dyes, dithiol metal complex dyes,metal phthalocyanine dyes, metal porphyrin dyes or ruthenium complexdyes are preferable, and the ruthenium complex dyes are particularlypreferable; however, the metal complex dyes are not limited to thosementioned above.

Next, as shown in FIG. 7B, by a lithographic technique, such as exposureand development, using a mask 95, the organic photoelectric conversionfilm 44 is exposed. For example, in the example shown in the figure, anorganic photoelectric conversion film 44 composed of a negative typephotosensitive organic photoelectric conversion material is used, andregions other than that in which the isolation region is formed areexposed. In this case, the non-exposed region corresponds to anisolation groove to be formed in the organic photoelectric conversionfilm 44 between the pixels.

Next, as shown in FIG. 7C, the organic photoelectric conversion film 44is developed, and whenever necessary, for example, a baking treatment isperformed, so that an isolation groove 48 is formed in the organicphotoelectric conversion film 44 between the pixels.

Since the organic photoelectric conversion film 44 has photosensitivity,unlike a related technique, while any etching damage is not done to theorganic photoelectric conversion film 44 by exposure and developmentprocesses, the isolation groove 48 can be formed in the organicphotoelectric conversion film 44. Incidentally, whenever necessary,before and/or after the exposure and/or the development, an appropriatebaking treatment is performed.

Next, as shown in FIG. 7D, a blocking film 46 is formed on the organicphotoelectric conversion film 44 so as to fill the isolation groove 48.A part of the blocking film 46 filled in the isolation groove 48 formsan isolation region 49. For this blocking film 46, any material may beused as long as it is transparent in a desired wavelength region of theorganic photoelectric conversion film 44 and has ionization potential(IP) different from that of the organic photoelectric conversion film 44and a second electrode 47 which is next formed. For example, for anorganic photoelectric conversion film 44 composed of quinacridone,aluminum quinoline (Alq3) or the like is effectively used. This blockingfilm 46 is relatively selected in consideration of the work function ofthe organic photoelectric conversion film 44 and that of the secondelectrode 47 and is not simply determined by one primary characteristic.For example, an organic SOG or a low dielectric constant film of apolyaryl ether, a polyimide, a fluorinated silicon oxide, a siliconcarbide, or the like may be used to form the blocking film 46. Inaddition, a transparent electrode material for the second electrode 47which is next formed or an organic photoelectric conversion materialforming the organic photoelectric conversion film 44 may also be usedwhen conditions are satisfied.

In addition, as a material forming the isolation region 49, any materialmay be used as long as it has an electrical isolation function(insulating properties) and an optical isolation (absorption orreflection) function.

For example, the isolation region 49 may be formed using a materialdifferent from that for the blocking film 46. For example, by a carbonblack resist having photosensitivity, the isolation region 49 can beformed. The isolation region 49 formed of a carbon black resist hasinsulating properties and also an optical isolation function by opticalabsorption of contained carbon.

Although not being shown in the figure, for example, when the isolationregion 49 is formed using the carbon black resist havingphotosensitivity, a carbon black resist film having photosensitivity isformed on the organic photoelectric conversion film 44, for example, bya coating method so as to fill the isolation groove 48.

Subsequently, an excess carbon black resist having photosensitivity onthe organic photoelectric conversion film 44 is removed so that thiscarbon black resist is allowed to remain only inside the isolationgroove 48, thereby forming the isolation region 49. Since this isolationregion 49 is able to absorb light by carbon of the carbon black resisthaving photosensitivity, an optical isolation function can be obtained.In addition, since insulating properties are imparted by carbon, theisolation region 49 has an insulating function.

In addition, although the isolation region 49 is formed to coincide withthe electrode isolation region 42, as for the relative relationshipbetween the width of the isolation region 49 and the width of theelectrode isolation region 42, the widths thereof may not be necessarilyequal to each other, and the position of the isolation region 49 may notnecessarily coincide with that of the electrode isolation region 42. Theeffect of the difference in size between the electrode isolation region42 and the isolation region 49 is the same as described above.

Since the organic photoelectric conversion film 44 has photosensitivity,after the organic photoelectric conversion film 44 is formed, whenexposure and development processes are performed thereon, the isolationgroove 48 can be formed therein. Accordingly, unlike a relatedtechnique, etching damage is not done to the organic photoelectricconversion film 44. Incidentally, whenever necessary, before and/orafter the exposure and/or development, an appropriate baking treatmentis performed.

In addition, the isolation region 49 may also be formed in the blockingfilm 46 provided on the organic photoelectric conversion film 44 tocorrespond to between the pixels by using a material different from thatfor the blocking film 46. In this case, the formation of the isolationgroove 48 is performed after the blocking film 46 is formed, and theisolation region 49 may be formed so as to fill the isolation groove 48.In addition, also in this case, the blocking film 46 and the organicphotoelectric conversion film 44 are each formed from a material havingphotosensitivity, and the isolation groove 48 is formed by exposure anddevelopment.

Next, the second electrode 47 is formed on the blocking film 46.

For the second electrode 47, a transparent electrode material is used.For example, there may be used indium oxide-based ITO (Sn is added as adopant to In₂O₃), SnO₂ (added with a dopant) as a tin oxide-basedmaterial, an aluminum zinc oxide (Al is added as a dopant to ZnO, suchas AZO) as a zinc oxide-based material, a gallium zinc oxide (Ga isadded as a dopant to ZnO, such as GZO), an indium zinc oxide (In isadded as a dopant to ZnO, such as IZO), CuI, InSbO₄, ZnMgO, CuInO₂,MgIn₂O₄, CdO, and ZnSnO₃.

Although not shown in the figure, a condenser lens (on-chip lens) 51condensing incident light on each of the photoelectric conversionportions 22 is formed on the second electrode 47.

When the condenser lenses 51 are formed, for example, an antireflectionlayer (not shown) may be formed on the surfaces of the condenser lenses51. In addition, an antireflection layer (not shown) may be formedbetween the condenser lenses 51 and the organic photoelectric conversionfilm 44.

As described above, the solid-state image pickup device 2 is formed.

In the method for manufacturing a solid-state image pickup device(second example), a manufacturing method in which a green signal isextracted from the organic photoelectric conversion film 44, and blueand red signals are extracted by the bulk spectroscopy is shown;however, another combination may also be used. Furthermore, besides thethree primary colors, combination among intermediate colors orarrangement of four colors or more may also be used. In addition,although the case in which the solid-state image pickup device 2 isapplied to a whole-area-open-type CMOS image sensor is shown by way ofexample, of course, it may also be applied to a common CMOS imagesensor. In addition, the spectroscopy in the photoelectric conversionportion 22 may also be performed using an organic color filter layer(not shown). In this case, the organic color filter layer may beprovided under the organic photoelectric conversion film 44 with anoptical transparent insulating film interposed therebetween or may beprovided on the organic photoelectric conversion film 44 with aninsulating film interposed therebetween.

In addition, in the solid-state image pickup device 2, as in the case ofthe first example of the manufacturing method, in order to reduce a darkcurrent and white output pixel defects, a film lowering an interfacestate and a film having a negative fixed charge (not shown) may besequentially formed on the surface of the photoelectric conversionportion 22. When the film lowering an interface state and the filmhaving a negative fixed charge are formed on the surface of thephotoelectric conversion portion 22 as described above, a holeaccumulation layer is formed at a light receiving surface side of thephotoelectric conversion portion 22.

In the method for manufacturing a solid-state image pickup device(second example), since the isolation region 49 performing optical andelectrical isolation is formed in the organic photoelectric conversionfilm 44 at the position corresponding to between the pixels 21, lightincident on one pixel is prevented from directly leaking in an adjacentpixel thereto. In addition, carriers generated by photoelectricalconversion of light incident on one pixel are prevented from leaking inan adjacent pixel thereto. That is, the isolation region 49 has anoptical isolation (absorption or reflection) function as well aselectrical insulating properties.

Since the electrode isolation region 42 and the isolation region 49 areformed to be connected to each other, leakage between the electrodeisolation region 42 and the isolation region 49 is prevented, and hencethe effect described above can be further enhanced.

Accordingly, the spatial resolution capability can be enhanced, and thecolor mixture can be suppressed, so that a high quality image can beobtained with high accuracy.

In addition, since the isolation groove 48 is formed using exposure anddevelopment processes, unlike a related technique, etching damage to theorganic photoelectric conversion film 44 is not generated. In addition,the degree of machining difficulty for forming the isolation region 49can be reduced.

3. Third Embodiment

[Example of Structure of Image Pickup Apparatus]

One example of the structure of an image pickup apparatus according to athird embodiment of the present invention will be described withreference to a block diagram in FIG. 8. This image pickup apparatus usesthe solid-state image pickup device according to an embodiment of thepresent invention.

As shown in FIG. 8, an image pickup apparatus 200 includes a solid-stateimage pickup device 210 in an image pickup portion 201. A lightcondensing optical portion 202 forming an image is provided at a lightcondensing side of this image pickup portion 201, and a signalprocessing portion 203 having, for example, a signal processing circuitwhich processes signals photoelectric-converted in the solid-state imagepickup device 210 into an image is connected to the image pickup portion201. In addition, an image signal processed by the signal processingportion 203 may be stored in an image storage portion (not shown). Inthe image pickup apparatus 200 described above, one of the solid-stateimage pickup devices 1 and 2 described in the above embodiments may beused as the solid-state image pickup device 210.

In the image pickup apparatus 200, since one of the solid-state imagepickup devices 1 and 2 according to the above embodiments of the presentinvention is used, the spatial resolution capability can be enhanced andthe color mixture can be suppressed as described above, so that a highquality image can be obtained with high accuracy. Accordingly, the imagequality can be improved.

In addition, the present invention is not limited to the image pickupapparatus 200 having the structure described above but may also beapplied to various image pickup apparatuses each including a solid-stateimage pickup device.

For example, the image pickup apparatus 200 described above may have aone-chip structure or may have a module structure in which an imagepickup portion and a signal processing portion or an optical system arecollectively formed to provide an image pickup function.

The “image pickup apparatus” in this embodiment indicates, for example,a camera or a mobile apparatus having an image pickup function. Inaddition, the concept of the “image pickup” includes, for example,fingerprint detection in a broad sense as well as a common image pickupusing a camera.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application JP 2009-185533 filedin the Japan Patent Office on Aug. 10, 2009, the entire content of whichis hereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1-15. (canceled)
 16. A solid state imaging device, comprising: aplurality of pixels in a semiconductor substrate, the pixels including aplurality of photoelectric conversion portions and MOS transistors; anorganic photoelectric conversion film on the semiconductor substrate;and a pixel isolation portion in the organic photoelectric conversionfilm, wherein the pixel isolation portion performs optical andelectrical isolation in the organic photoelectric conversion film. 17.The solid state imaging device according to claim 16, wherein the pixelisolation portion includes an impurity region.
 18. The solid stateimaging device according to claim 17, wherein the impurity regionincludes at least one of nitrogen (N), oxygen (O), carbon (C), hydrogen(H), helium (He), titanium (Ti), zirconium (Zr), hafnium (Hf), ortungsten (W).
 19. The solid state imaging device according to claim 17,wherein the impurity region extends to the top and the bottom of theorganic photoelectric conversion film.
 20. The solid state imagingdevice according to claim 19, wherein the impurity region divides thephotoelectric conversion film into separate areas.
 21. The solid stateimaging device according to claim 16, wherein the pixel isolationportion includes a region in which molecular bonds in the organicphotoelectric conversion film are broken.
 22. The solid state imagingdevice according to claim 16, wherein the isolation portion includes aphotosensitive material.
 23. The solid state imaging device according toclaim 16, wherein the organic photoelectric conversion film comprises anorganic photoelectric conversion material having photosensitivity. 24.The solid state imaging device according to claim 23, wherein theorganic photoelectric conversion material having photosensitivityincludes an organic photoelectric conversion material and aphotosensitive material.
 25. The solid state imaging device according toclaim 23, wherein the organic photoelectric conversion material havingphotosensitivity includes an organic photoelectric conversion materialhaving a photosensitive reactive group.
 26. The solid state imagingdevice according to claim 16, further comprising: a blocking filmprovided on the organic photoelectric conversion film.
 27. The solidstate imaging device according to claim 26, wherein the pixel isolationportion is provided in the blocking film at a position corresponding tobetween the pixels.
 28. An image pickup apparatus comprising: a lightcondensing optical portion condensing incident light; an image pickupportion having a solid state imaging device which receives lightcondensed by the light condensing optical portion and performsphotoelectrical conversion of the light; and a signal processing portionconfigured to process a signal that is photoelectrically-converted bythe solid state imaging device and is output from the image pickupportion, wherein the solid state imaging device includes: a plurality ofpixels in a semiconductor substrate, the pixels including a plurality ofphotoelectric conversion portions and MOS transistors; an organicphotoelectric conversion film on the semiconductor substrate; and apixel isolation portion in the organic photoelectric conversion film,wherein the pixel isolation portion performs optical and electricalisolation in the organic photoelectric conversion film.
 29. The imagepickup apparatus of claim 28, wherein the pixel isolation portionincludes an impurity region.
 30. The image pickup apparatus of claim 29,wherein the impurity region includes at least one of nitrogen (N),oxygen (O), carbon (C), hydrogen (H), helium (He), titanium (Ti),zirconium (Zr), hafnium (Hf), or tungsten (W).
 31. The image pickupapparatus of claim 29, wherein the impurity region extends to the topand the bottom of the organic photoelectric conversion film.
 32. Theimage pickup apparatus of claim 31 wherein the impurity region dividesthe photoelectric conversion film into separate areas.
 33. The imagepickup apparatus of claim 28, wherein the isolation portion includes aphotosensitive material.
 34. The image pickup apparatus of claim 28,further comprising: a blocking film provided on the organicphotoelectric conversion film.
 35. The image pickup apparatus of claim28, wherein the pixel isolation portion is provided in the blocking filmat a position corresponding to between the pixels.